Anorexia: Key Mortality Risk Factor Revealed

Caroline Cassels

Aug 13, 2013

Duration of anorexia nervosa (AN) appears to be the prime risk factor for premature death in girls and women with eating disorders, new research shows.

A 20-year follow-up study showed that treatment-seeking patients who had AN for a period of 0 to 15 years had more than a 3-fold increased risk for death compared with the general population, whereas for those who had AN for 16 to 30 years, the risk for mortality was increased almost 7-fold.

“Our analyses revealed that patients with lifetime anorexia nervosa had higher premature mortality rates than the general population and that risk of premature death was highest in the first 10 years of follow-up and among individuals with the longest duration of illness,” the authors, led by Debra L. Franko, PhD, Northeastern University in Boston, Massachusetts, write.

The study is published in the August issue of the American Journal of Psychiatry.

Timing of Mortality Risk Uncertain

Although it is well known that the mortality rate in AN patients is higher than in patients with other psychiatric disorders, the investigators note that it is not clear from the current literature whether there is a point of peak mortality in the course of the illness. It is also uncertain whether there are differences between patients who die relatively early in the disease course vs those who die later.

To better understand timing and predictors of mortality in this population, beginning in 1987, the investigators conducted a longitudinal study of 246 treatment-seeking patients with AN or bulimia nervosa (BN). The patients were interviewed every 6 months for a median of 9.5 years to obtain weekly ratings of eating disorder symptoms, comorbidity, treatment participation, and psychosocial functioning.

A total of 51 patients had AN of the restricting type, 85 were diagnosed with AN, binge eating/purging type, and 110 had BN.

Of these, 186 (76%) were identified as having lifetime presence of AN. Because previous research indicates that death among individuals with an intake diagnosis of BN might be attributable to a lifetime diagnosis of AN, these patient were also assessed for AN.

During the entire study period, 16 women died. Of these, 14 had a lifetime history of AN, and 4 of these deaths were by suicide. Two women with BN who had no history of AN died.

The standardized mortality ratio was 4.37 (95% confidence interval [CI], 2.4 – 7.3) for lifetime AN and 2.33 (95% CI, 0.3 – 0.8) for BN with no history of AN.

The risk for patients with lifetime AN was highest among individuals in the first 10 years of follow-up, as well as among individuals with the longest duration of illness.

The researchers note that most of the deaths occurred during the first 10 years of the study (10/186 died). For the follow-up duration from 0 to 10 years, the standardized mortality ratio was 7.7 (95% CI, 3.7 – 14.2). During the 10- to 20-year follow-up period (4/176 died), the standardized mortality ratio was 0.7 (95% CI, 0.2 – 1.7).

The standardized mortality was 3.2 (95% CI, 0.9-8.3) for patients who reported lifetime AN for 0 to 15 years and 6.6 (95% CI, 3.2 – 12.1) for those reporting a duration of illness of longer than 15 to 30 years.

The fact that most women died in the first decade of study follow-up is likely explained by the fact that coming into the study, most of the women had already experienced a long duration of illness. With 1 exception, those who died reported an illness duration of between 7 and 25 years.

Multivariate predictors of mortality included alcohol abuse; low body mass index; poor psychosocial functioning, particularly as it relates to employment; fair to poor interpersonal relationships with friends and siblings; and being single.

“Our findings highlight the need for early identification and intervention and suggest that among those with a long duration of illness, particularly when substance abuse, low weight, or poor psychosocial function are also present, the risk for mortality increases substantially,” the investigators conclude.

Clinical Implications

In an accompanying editorial, Scott Crow, MD, University of Minnesota, in Minneapolis, notes the study’s findings “further reinforce the public health importance of eating disorders.”

“The temporal course of mortality observed here argues strongly for increased emphasis on early identification of eating disorders and the potential importance of early treatment for these disorders,” he writes.

Dr. Crow adds that there is evidence that psychotherapies delivered to teens may be more effective than therapies delivered in adulthood and may reduce mortality.

Finally, he writes, although suicide is recognized as a risk in many psychiatric illnesses, it may be underappreciated in eating disorders. The study results reveal that suicide mortality in this patient population is “very high” and “may be concentrated early in the illness. Thus, intensive monitoring of suicidality early in the illness course may be critical.”

The authors of the study report no relevant financial relationships. Dr. Crow reports that he has received research support from Alkermes, Novartis, and Shire.